JP2017075198A - Acrylic resin composition and electronic component - Google Patents

Abstract

An acrylic resin composition having high transparency after curing and high airtightness is provided.
An acrylic resin composition comprising (A) an acrylic polymer, (B) an acrylic monomer, and (C) a polymerization initiator. (B) The acrylic monomer contains a (meth) acrylic acid ester having a linear or branched alkyl group and a (meth) acrylic acid ester having an alicyclic group.
[Selection figure] None

Description

  The present invention relates to an acrylic resin composition and an electronic component.

  Conventionally, an epoxy resin is generally used as a sealing material for an optical device or an optical component material, particularly a light emitting diode (LED) element.

  It has been attempted to use silicone resin as a molding material for LED elements (see Patent Document 1 and Patent Document 2) and as a color filter material (see Patent Document 3). Few.

  In recent years, while white LEDs have been attracting attention, problems such as yellowing due to ultraviolet rays etc. of epoxy resin-based sealing materials, which has not been a problem so far, and cracks accompanying an increase in the amount of heat generated due to miniaturization have occurred, Response is an urgent need. As these countermeasures, use of a cured silicone resin having a large amount of phenyl groups in the molecule has been studied (see Patent Document 4). However, since the silicone resin system is hardened rapidly at a high temperature, cracks and film loss occur, so that it was necessary to cure over time while gradually raising the temperature from a low temperature.

Japanese Patent Laid-Open No. 10-228249 Japanese Patent Laid-Open No. 10-242513 JP 2000-123981 A JP 2010-180323 A

  Therefore, transparent sealing materials that can be cured in a short time have been developed, but practical application has been difficult.

  The present invention has been made in view of the above circumstances, and provides a resin composition that can be cured in a short time by a radical polymerization reaction and that has high transparency and high airtightness after curing. With the goal.

  The present invention relates to an acrylic resin composition containing (A) an acrylic polymer, (B) an acrylic monomer, and (C) a polymerization initiator. This invention provides the acrylic resin composition in which the (B) acrylic monomer contains the (meth) acrylic acid ester which has a linear or branched alkyl group, and the (meth) acrylic acid ester which has an alicyclic group. . As a result, the resin composition can be cured in a short time, and both high transparency and high airtightness after the resin composition is cured can be achieved. Furthermore, by using together (A) acrylic polymer and (B) acrylic monomer, appropriate fluidity | liquidity can be provided to the acrylic resin composition before hardening.

  In general, an acrylic polymer has high transparency, but it needs to be dissolved in a solvent because of insufficient fluidity. However, there is a problem that the solvent is volatilized with the curing and the moldability is poor.

Accordingly, the present inventors have found that fluidity can be improved by dissolving (A) the acrylic polymer in (B) the acrylic monomer, and thereby the acrylic resin composition can be used as a liquid material or a potting material. It became easy to use. Furthermore, as (B) acrylic monomer, by using together (meth) acrylic acid ester having an alicyclic skeleton in the ester part and (meth) acrylic acid ester having a linear or branched alkyl group in the ester part, It has been found that both high transparency after curing and high airtightness can be achieved while ensuring fluidity. When (B) acrylic monomer is used in combination with (meth) acrylic acid ester having an alicyclic skeleton in the ester portion and (meth) acrylic acid ester having a linear or branched alkyl group in the ester portion, (A) acrylic Since an acrylic polymer similar to the molecular skeleton of the polymer is formed, the compatibility is improved, and it is considered that high transparency and high airtightness after curing can be exhibited. Furthermore, since it is an acrylic resin composition whose curing reaction is a radical polymerization reaction, it is considered that curing in a short time is possible.
Since the acrylic resin composition in the present invention is excellent in cured product and transparency, it is difficult to become clouded even when left under high temperature and high humidity. Therefore, optical materials such as sealing materials for light emitting diode (LED) elements, optical lens materials, etc. It can be used as a cured product suitable for a member.

（式（Ｉ）中、Ｘは置換基を有していてもよい炭素数５〜２２の脂環基を示し、Ｒ_１は水素原子又はメチル基を示す。）

（式（ＩＩ）中、Ｙは置換基を有していてもよい炭素数１〜１０の直鎖又は分岐アルキル基を示し、Ｒ_２は水素原子又はメチル基を示す。）

（式（ＩＩＩ）中、Ｚはカルボキシル基、ヒドロキシル基、酸無水物基、アミノ基、アミド基、エポキシ基及びニトリル基からなる群より選ばれる少なくとも１種の官能基を含む置換基を示し、Ｒ_３は水素原子又はメチル基を示す。） (A) The acrylic polymer may contain at least one selected from the following general formulas (I), (II) and (III) as a structural unit.

(In formula (I), X represents an alicyclic group having 5 to 22 carbon atoms which may have a substituent, and R ₁ represents a hydrogen atom or a methyl group.)

(In formula (II), Y represents a linear or branched alkyl group having 1 to 10 carbon atoms which may have a substituent, and R ₂ represents a hydrogen atom or a methyl group.)

(In formula (III), Z represents a substituent containing at least one functional group selected from the group consisting of a carboxyl group, a hydroxyl group, an acid anhydride group, an amino group, an amide group, an epoxy group and a nitrile group; R ₃ represents a hydrogen atom or a methyl group.)

  (A) The acrylic polymer may contain a structural unit derived from the same acrylic monomer as at least one of (B) acrylic monomers.

  The acrylic resin composition may further contain a phosphor and may be liquid at 25 ° C. Moreover, the said acrylic resin composition can be used suitably as a potting material.

  Furthermore, the present invention relates to an electronic component including a light emitting element or a light receiving element and a sealing member that seals the light emitting element or the light receiving element. The present invention provides an electronic component in which the sealing member is a cured product of the acrylic resin composition.

According to the present invention, an acrylic resin composition having high transparency after curing and high airtightness can be provided.
Moreover, according to this invention, the electronic component using such an acrylic resin composition can be provided.

It is sectional drawing which shows one Embodiment of the LED package using an acrylic resin composition. It is process drawing which shows one Embodiment of the preparation process (thermosetting type) of the LED package using an acrylic resin composition. It is process drawing which shows one Embodiment of the preparation process (photocuring type) of the LED package using an acrylic resin composition.

  Hereinafter, preferred embodiments of the present invention will be described, but the present invention is not limited to these embodiments. In this specification, “(meth) acryl” means “acryl” or “methacryl” corresponding to it. The same applies to other similar expressions such as (meth) acryloyl. Moreover, (meth) acrylic acid ester may be described as (meth) acrylate.

  In the present invention, “transparency” means that the visible light transmittance, that is, the visible light transmittance of at least a wavelength of 450 nm is good. Further, “airtightness” refers to a metal part (for example, a silver lead frame part) due to impurities that permeate the cured acrylic resin composition when the LED package encapsulated with the acrylic resin composition is exposed in the presence of sulfur. ) Is not substantially oxidized, and the luminance is not substantially reduced as compared with the initial value.

[Acrylic resin composition]
The acrylic resin composition according to this embodiment includes (A) an acrylic polymer, (B) an acrylic monomer, and (C) a polymerization initiator. Hereinafter, each component will be described.

((A) acrylic polymer)
The acrylic polymer used in the present embodiment refers to a polymer obtained by polymerizing one acrylic monomer having one (meth) acryloyl group in the molecule, or a copolymer obtained by combining two or more. Within the scope of the present invention, a compound having two or more (meth) acryloyl groups in the molecule, or a polymerizable compound having no (meth) acryloyl group ((meth) acrylonitrile, styrene, acetic acid) Vinyl, ethylene, propylene, etc.) and a monomer having one polymerizable unsaturated bond in the molecule, and a compound having two or more polymerizable unsaturated bonds in the molecule such as divinylbenzene) are copolymerized with an acrylic monomer. It may be made. From such a viewpoint, the acrylic polymer used in this embodiment has 1 to 100% by mass of an acrylic monomer having one (meth) acryloyl group in the molecule based on the total amount of the acrylic polymer. When it has 50-100 mass%, it is more preferable from a compatible viewpoint, and when it has 70-100 mass%, it is still more preferable from a compatible and storage stability viewpoint.

（式（Ｉ）中、Ｘは置換基を有していてもよい炭素数５〜２２の脂環基を示す。Ｒ_１は水素原子又はメチル基を示す。）

（式（ＩＩ）中、Ｙは置換基を有していてもよい炭素数１〜１０の直鎖又は分岐アルキル基を示す。Ｒ_２は水素原子又はメチル基を示す。）

（式（ＩＩＩ）中、Ｚはカルボキシル基、ヒドロキシル基、酸無水物基、アミノ基、アミド基、エポキシ基及びニトリル基からなる群より選ばれる少なくとも１種の官能基を含む置換基を示す。Ｒ_３は水素原子又はメチル基を示す。） The component (A) preferably has at least one selected from the following general formulas (I), (II) and (III) as a structural unit. Thereby, the acrylic resin composition which has higher transparency after hardening and higher airtightness can be obtained.

(In formula (I), X represents an alicyclic group having 5 to 22 carbon atoms which may have a substituent. R ₁ represents a hydrogen atom or a methyl group.)

(In formula (II), Y represents a linear or branched alkyl group having 1 to 10 carbon atoms which may have a substituent. R ₂ represents a hydrogen atom or a methyl group.)

(In formula (III), Z represents a substituent containing at least one functional group selected from the group consisting of a carboxyl group, a hydroxyl group, an acid anhydride group, an amino group, an amide group, an epoxy group and a nitrile group. R ₃ represents a hydrogen atom or a methyl group.)

  From the viewpoint of improving the transparency, an acrylic polymer having the structural unit of the above general formula (I) is preferable, and from the viewpoint of reducing the elastic modulus of the cured product in order to relieve the stress accompanying curing, the above general formula An acrylic polymer having the structural unit (II) is preferred. Moreover, the acrylic polymer which has a structural unit of the said general formula (III) from a viewpoint of improving the airtightness to the to-be-adhered body of hardened | cured material is preferable.

  In the structural unit of the general formula (I), X is preferably a cyclohexyl group, a bicyclopentanyl group, an isobornyl group, a norbornyl group, a tricyclodecanyl group, or an adamantyl group from the viewpoint of transparency.

（式（ＩＶ）中、Ｒ_４は、水素原子又はメチル基を示す。Ｒ_５及びＲ_６はそれぞれ独立に、直鎖アルキル基を示す。） In the structural unit of the general formula (II), Y is preferably a linear or branched alkyl group from the viewpoint of low elasticity. Especially, it is more preferable that the structural unit of general formula (II) is a structural unit of the following general formula (IV).

(In formula (IV), R ₄ represents a hydrogen atom or a methyl group. R ₅ and R ₆ each independently represents a linear alkyl group.)

  The structural unit of the general formula (III) is at least one selected from the group consisting of a carboxyl group, a hydroxyl group, an acid anhydride group, an amino group, an amide group, an epoxy group, and a nitrile group from the viewpoint of adhesion. A substituent containing a functional group of a species is preferable. Among these, Z is more preferably a substituent containing an epoxy group from the viewpoint of improving the adhesion of the cured product and reducing the odor. High adhesion is obtained with ring-opening polymerization of the epoxide.

  The acrylic polymer may contain a structural unit derived from a polymerizable compound having no (meth) acryloyl group. In the present embodiment, from the viewpoint of preventing coloration due to bonding with moisture in the air, as the polymerizable compound having no (meth) acryloyl group described above, styrene, vinyl acetate, ethylene, propylene, and the like are used. It is preferable to use it.

  The (A) acrylic polymer preferably contains a structural unit derived from the same acrylic monomer as at least one of the (B) acrylic monomers.

  As the component (A) according to the present embodiment, for example, one synthesized by the following method can be used, but is not limited thereto.

300 g of tricyclo [5.2.1.0 ^2,6 ] dec-8-yl acrylate (trade name: “FA-513-A” (Hitachi Chemical Co., Ltd.)), 350 g of butyl acrylate (BA), methacrylic acid 300 g of butyl (BMA), 50 g of glycidyl methacrylate (GMA) and 50 g of 2-ethylhexyl methacrylate (2EHMA) were mixed, and 5 g of lauroyl peroxide and n-octyl mercaptan as a chain transfer agent were added to the resulting monomer mixture. .45 g is dissolved to make a mixed solution.
To a 5 liter autoclave equipped with a stirrer and a condenser, 0.04 g of polyvinyl alcohol and 2000 g of ion-exchanged water are added as a suspending agent, and the above mixture is added with stirring. Polymerization is carried out for 5 hours and then at 90 ° C. for 2 hours to obtain resin particles. By washing the resin particles with water, dehydrating and drying, the component (A) can be obtained.

  In this embodiment, the mixing ratio of each monomer is 5 to 94.5 parts by mass of the monomer having the structural unit of the general formula (I), and the single monomer having the structural unit of the general formula (II). 5 to 65 parts by mass of the monomer, 0.5 to 30 parts by mass of the monomer having the structural unit of the general formula (III), and 0 to 90 parts by mass of the monomer copolymerizable therewith, The mixing ratio is preferably such that the mass part is 100 parts by mass.

  The blending amount of the monomer having the structural unit of the general formula (I) in this embodiment is preferably 5 to 94.5 parts by mass, but 10 to 80 parts by mass in terms of transparency. More preferred.

  The blending amount of the monomer having the structural unit of the general formula (II) in this embodiment is preferably 5 to 65 parts by mass, more preferably 15 to 55 parts by mass from the viewpoint of flexibility. .

  The blending amount of the monomer having the structural unit of the general formula (III) in this embodiment is preferably 0.5 to 30 parts by mass, but 1 to 20 parts by mass is airtight. More preferred.

  In this embodiment, the (A) acrylic polymer is preferably 1 to 80 parts by mass from the viewpoint of moldability with respect to a total amount of 100 parts by mass with the (B) acrylic monomer, It is preferable that it is 5-40 mass parts from a viewpoint of workability | operativity improvement.

  The weight average molecular weight (Mw) of the component (A) according to this embodiment is preferably 200000 to 1000000 from the viewpoint of maintaining transparency, and 200000 to 700000 from the viewpoint of solubility in acrylic monomers. It is more preferable that The weight average molecular weight (Mw) is measured as follows.

It is measured by GPC method using tetrahydrofuran (THF) as an eluent and is calculated in terms of standard polystyrene. The details of the GPC method are as follows.
・ Device name: HLC-8220GPC (product name, Tosoh Corporation)
Column: Gelpack R-420, R-430, R-440 (product name, Hitachi Chemical Co., Ltd.)
-Detector: RI detector-Column temperature: 40 ° C
・ Eluent: Tetrahydrofuran (THF)
・ Flow rate: 1 ml / min ・ Standard: Polystyrene

  (A) As a commercial item of an acrylic polymer, HTR-860P-3 (Mw = 700000-900000, Nagase ChemteX Corporation) is mentioned, for example.

((B) acrylic monomer)
Examples of the (B) acrylic monomer according to this embodiment include (B1) a (meth) acrylic monomer having a linear or branched alkyl group, and (B2) a (meth) acrylic single monomer having an alicyclic group. Body, (B3) polyfunctional (meth) acrylic monomer, and (B4) (meth) acrylic monomer having a functional group.

((B1) (Meth) acrylic monomer having linear or branched alkyl group)
The (meth) acrylic monomer having a linear or branched alkyl group preferably has a linear or branched group in the ester portion, and is a (meth) acrylic acid ester having one (meth) acryloyl group. Is preferred. Here, the ester portion in the present invention means a portion of R _{2 in} the ester bond R ₁ —C (═O) —O—R ₂ . The (B1) may have a plurality of (meth) acryloyl groups. The straight or branched alkyl group of the ester moiety may be directly bonded to the oxygen atom of the ester group. As a linear or branched alkyl group of an ester part, a C1-C20 linear or branched alkyl group is mentioned, for example. If the carbon number is 20 or less, the elastic modulus tends to be low. The number of carbon atoms is more preferably 2-18 from the viewpoint of solubility of the acrylic polymer, and further preferably 4-18 from the viewpoint of TCT resistance. The structure of the alkyl group may be linear or branched, but has a linear or tertiary carbon from the viewpoint that mass loss due to thermal decomposition hardly occurs at low temperatures and that coloration is unlikely to occur due to deterioration. Preferred is a branched alkyl group. From the above viewpoint, a (meth) acrylic acid ester having a branched alkyl group having 1 to 20 carbon atoms and having no linear or tertiary carbon is more preferable.

  Examples of the (meth) acrylic acid ester having an alkyl group having 1 to 20 carbon atoms in the ester part include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, and (meth) acrylic acid. i-propyl, n-butyl (meth) acrylate, i-butyl (meth) acrylate, sec-butyl (meth) acrylate, pentyl (meth) acrylate, n-hexyl (meth) acrylate, (meth) Examples include n-octyl acrylate, 2-ethylhexyl (meth) acrylate, decyl (meth) acrylate, dodecyl (meth) acrylate, octadodecyl (meth) acrylate, and the like.

  Among these, from the viewpoint of preventing cracking of the cured product and peeling from the LED package, n-butyl methacrylate, pentyl methacrylate, n-hexyl methacrylate, 2-ethylhexyl methacrylate, dodecyl acrylate, lauryl acrylate, acrylic Acid dododecyl and the like are more preferable. These can be used alone or in combination of two or more.

((B2) (Meth) acrylic monomer having alicyclic group)
The (meth) acrylic monomer having an alicyclic group is preferably a (meth) acrylic acid ester having an alicyclic group in the ester portion. Note that the ester unit in the present invention means a part of _{R 2} in the ester bond _{R 1 -C (= O) -O} -R 2. Here, the alicyclic group of the ester part may be directly bonded to the oxygen atom of the ester part. Examples of the alicyclic group include cycloalkane, bicycloalkane, novolak type and isobornyl type. Among these, from the viewpoint of improving transparency, it is preferable to use a bicycloalkane or a novolac type.

As the (meth) acrylic acid ester having an alicyclic group in the ester portion, cyclopentyl (meth) acrylate, cyclopentanyl (meth) acrylate, dicyclopentanyl (meth) acrylate, cyclohexyl (meth) acrylate, (Meth) acrylic acid methylcyclohexyl, (meth) acrylic acid trimethylcyclohexyl, (meth) acrylic acid norbornyl, (meth) acrylic acid norbornylmethyl, (meth) acrylic acid phenylnorbornyl, (meth) acrylic acid cyanonoryl Bornyl, isobornyl (meth) acrylate, bornyl (meth) acrylate, menthyl (meth) acrylate, fentil (meth) acrylate, adamantyl (meth) acrylate, dimethyladamantyl (meth) acrylate, (meth) acrylic Acid tricyclo [5.2.1 0 ^2,6] deca-8-yl, (meth) acrylic acid tricyclo [5.2.1.0 ^2,6] deca-4-methyl, and (meth) cyclodecyl acrylate.

Among these, from the viewpoint of transparency, cyclopentanyl acrylate, cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, norbornyl (meth) acrylate, norbornylmethyl (meth) acrylate, (meth) Tricyclo [5.2.1.0 ^2,6 ] deca-8-yl acrylate, tricyclo [5.2.1.0 ^2,6 ] dec-4-methyl (meth) acrylate, (meth) acrylic acid Adamantyl, cyclopentyl (meth) acrylate, methylcyclohexyl (meth) acrylate, trimethylcyclohexyl (meth) acrylate, bornyl (meth) acrylate, menthyl (meth) acrylate, fentil (meth) acrylate, (meth) acrylic Dimethyl adamantyl acid, cyclodecyl (meth) acrylate and the like are preferable.

Furthermore, from the viewpoint of improving transparency, cyclopentanyl acrylate, cyclohexyl acrylate, isobornyl acrylate, norbornyl acrylate, norbornyl methyl acrylate, tricyclo [5.2.1.0 ^2,6 ] decyl acrylate 8-yl, tricyclo [5.2.1.0 ^2,6 ] dec-4-methyl acrylate, adamantyl acrylate, and the like are more preferable. These can be used alone or in combination of two or more.

  The (meth) acrylic monomer having an alicyclic group may contain a polyfunctional (meth) acrylic monomer. Examples of the polyfunctional (meth) acrylic monomer having an alicyclic group include cyclohexane 1,4-dimethanol di (meth) acrylate, cyclohexane 1,3-dimethanol di (meth) acrylate, and tricyclodecane dimethylol di (meth). Acrylate (Nippon Kayaku Co., Ltd., KAYARAD R-684, tricyclodecane dimethylol diacrylate, etc.), and tricyclodecane dimethanol di (meth) acrylate (Shin Nakamura Chemical Co., Ltd., A-DCP, tricyclodecane dimethanol) And diacrylate).

((B3) polyfunctional (meth) acrylic monomer)
The polyfunctional (meth) acrylic monomer has two or more (meth) acryloyl groups and is not particularly limited as long as it is other than (B1) and (B2). As such a polyfunctional (meth) acrylic monomer, a polyfunctional (meth) acrylic monomer having a linear or branched alkyl skeleton, a polyfunctional (meth) acrylic monomer having a dioxane glycol skeleton, a functional group And polyfunctional (meth) acrylic monomers having

  From the viewpoint of preventing cracks in the cured product and peeling from the LED package, it is preferable to use a polyfunctional (meth) acrylic monomer having a linear skeleton. On the other hand, from the viewpoint of improving the transparency of the cured product, it is preferable to use a polyfunctional (meth) acrylic monomer having a dioxane glycol skeleton.

  As the polyfunctional (meth) acrylic monomer, a (meth) acrylic monomer having two (meth) acryloyl groups, for example, ethylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate 1,6-hexanediol di (meth) acrylate, nonanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, dicyclopentanyl di (meth) acrylate, ethylene oxide modified 1,6-hexanediol di (Meth) acrylate, (poly) ethylene oxide modified neopentyl glycol di (meth) acrylate, hydroxypivalic acid neopentyl glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate Ethylene oxide modified bisphenol A type di (meth) acrylate, (preferably polyethylene oxide modified bisphenol A type di (meth) acrylate, more preferably ethylene oxide 5-15 mol modified bisphenol A type (meth) acrylate), (poly ) Ethylene oxide modified phosphoric acid di (meth) acrylate, dioxane glycol di (meth) acrylate and the like. Among the above, from the viewpoint of improving the transmittance of the cured product, dioxane glycol di (meth) acrylate (Nippon Kayaku Co., Ltd., KAYARAD R-604, dioxane glycol diacrylate, etc.) and the like are preferable. On the other hand, 1,4-butanediol di (meth) acrylate (Hitachi Chemical Co., Ltd., FA-124AS, 1,4-butanediol diacrylate, etc.), nonane from the viewpoint of preventing the cured product crack and peeling from the LED package. Diol di (meth) acrylate (Hitachi Chemical Co., Ltd., FA-129AS, nonanediol diacrylate, etc.) and the like are preferably used.

（式（Ｖ）中、Ｒ_９は水素原子又はメチル基を示す。Ｚはカルボキシル基、ヒドロキシル基、酸無水物基、アミノ基、アミド基及びエポキシ基からなる群より選ばれる少なくとも１種の官能基を有する置換基を示す。） ((B4) (meth) acrylic monomer having functional group)
The (meth) acrylic monomer having a functional group is a group consisting of a carboxyl group, a hydroxyl group, an acid anhydride group, an amino group, an amide group, and an epoxy group in the molecule as shown in the following general formula (V). A (meth) acrylic monomer having at least one functional group selected from the above is preferable.

(In formula (V), R ₉ represents a hydrogen atom or a methyl group. Z represents at least one functional group selected from the group consisting of a carboxyl group, a hydroxyl group, an acid anhydride group, an amino group, an amide group, and an epoxy group. A substituent having a group is shown.)

  Examples of the (meth) acrylic monomer having a functional group include 2- (meth) acryloyloxyethyl succinic acid, 2- (meth) acryloyloxyethyl phthalic acid, 2- (meth) acryloyloxyethyl hexahydrophthalic acid, 2 -(Meth) acryloyloxypropyl hexahydrophthalic acid-containing (meth) acrylic monomers (compounds wherein Z is a substituent containing a carboxyl group in the above formula (V)), (meth) acrylic acid, etc. Unsaturated carboxylic acid (compound in which Z is a hydroxyl group in the above formula (V)), hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, cyclohexanedimethanol mono (Meth) acrylate, N-methylol (meth) acrylamide, etc. Acid anhydride group-containing (meth) acrylic monomers such as droxyl group-containing (meth) acrylic monomer, trimellitic anhydride (meth) acryloyloxyethyl ester, cyclohexanetricarboxylic acid anhydride (meth) acryloyloxyethyl ester ( A compound in which Z is a substituent containing an acid anhydride group in the above formula (V)), diethylaminoethyl (meth) acrylate, -2,2,6,6-tetramethylpiperidinyl (meth) acrylate, An amino group-containing (meth) acrylic monomer such as (meth) acrylic acid-1,2,2,6,6-pentamethylpiperidinyl (in the above formula (V), Z is a substituent containing an amino group) Certain compounds), amide group-containing (meth) acrylic monomers such as (meth) acrylamide and N- (meth) acryloylglycinamide (in the above formula (V)) A compound in which Z is a substituent containing an amide group), glycidyl (meth) acrylate, glycidyl α-ethyl (meth) acrylate, glycidyl α-n-propyl acrylate, glycidyl α-n-butyl acrylate, 2- (2,3-epoxypropoxy) ethyl (meth) acrylate, 3- (2,3-epoxypropoxy) propyl (meth) acrylate, 4- (2,3-epoxypropoxy) butyl (meth) acrylate, 5- (2,3-epoxypropoxy) pentyl (meth) acrylate, 6- (2,3 epoxypropoxy) hexyl (meth) acrylate, (meth) acrylic acid-3,4-epoxybutyl, (meth) acrylic acid-4, 5-epoxypentyl, (meth) acrylic acid-6,7-epoxyheptyl, α-ethyl (meth) acrylic acid 6,7-epoxyheptyl, (meth) acrylic acid-3-methyl-3,4-epoxybutyl, (meth) acrylic acid-4-methyl-4,5-epoxypentyl, (meth) acrylic acid-5-methyl Epoxy group-containing (meth) acrylic monomers such as -5,6-epoxyhexyl, (meth) acrylic acid-β-methylglycidyl, α-ethyl (meth) acrylic acid-β-methylglycidyl (formula (V) above) In which Z is a substituent containing an epoxy group).

  Among these, an epoxy group-containing (meth) acrylic monomer is preferable in terms of airtightness, and glycidyl methacrylate is more preferable.

  In the present embodiment, the (B) acrylic monomer is not particularly limited as long as it does not impair the transparency and airtightness of the cured product, and the following monomers may be blended.

<Aromatic acrylic acid compound>
Examples of the aromatic acrylic compound include benzyl (meth) acrylate, phenoxyethyl (meth) acrylate, naphthyl (meth) acrylate, and the like.

<Aromatic vinyl compound>
As aromatic vinyl compounds, 4-vinylpyridine, 2-vinylpyridine, α-methylstyrene, α-ethylstyrene, α-fluorostyrene, α-chlorostyrene, α-bromostyrene, fluorostyrene, chlorostyrene, bromostyrene , Methylstyrene, methoxystyrene, (o-, m-, p-) hydroxystyrene, styrene and the like.

<Unsaturated dicarboxylic acid anhydrides>
Examples of unsaturated dicarboxylic acid anhydrides include maleic anhydride.

<N-substituted maleimides>
N-substituted maleimides include N-methylmaleimide, N-ethylmaleimide, N-propylmaleimide, Ni-propylmaleimide, N-butylmaleimide, Ni-butylmaleimide, Nt-butylmaleimide, N -Laurylmaleimide, N-cyclohexylmaleimide, N-benzylmaleimide, N-phenylmaleimide and the like.

  In addition, (B) acrylic monomers can be used individually by 1 type or in combination of 2 or more types.

  The blending amount of the (B) acrylic monomer is preferably 1 to 99 parts by mass, more preferably 5 to 95 parts by mass with respect to 100 parts by mass of the total amount of the (A) acrylic polymer and the (B) acrylic monomer. Parts, more preferably 10 to 90 parts by mass. By making the said compounding quantity into the said range, foaming, turbidity, coloring, a crack, etc. of hardened | cured material can be prevented.

((C) polymerization initiator)
As the (C) polymerization initiator according to this embodiment, (C1) a thermal polymerization initiator or (C2) a photopolymerization initiator can be used. These may be used in combination. Thereby, it is possible to design not only a thermosetting system but also a photocuring system. For example, it is possible to shorten the curing time by employing an exposure process.

  (C1) As the thermal polymerization initiator, dilauroyl peroxide (commercial product: “Perroyl L” (Nippon Yushi Co., Ltd.)), 1,1,3,3-trimethylbutylperoxy-2-ethylhexanate (commercial product: “Perocta O” (Nippon Yushi Co., Ltd.)), benzoyl peroxide (commercial product: “Nyper BW” (Nippon Yushi Co., Ltd.)), 1,1-di (t-hexylperoxy) cyclohexane (commercial product: “Perhexa HC”) (Nippon Yushi Co., Ltd.)), t-butylcumyl peroxide (commercial product: “Perbutyl C” (Nippon Yushi Co., Ltd.)), n-butyl 4,4-di- (t-butylperoxy) valerate (commercial product) : "Perhexa V" (Nippon Yushi Co., Ltd.)), Dicumyl peroxide (commercial product: "Park Mill D" (Nippon Yushi Co., Ltd.)), etc. It is below.

  In addition, (C1) thermal polymerization initiator can be used individually by 1 type or in combination of 2 or more types.

  (C1) The blending amount of the thermal polymerization initiator is preferably 0.1 to 30 parts by mass, and more preferably 0.1 parts to 100 parts by mass of the total amount of (A) acrylic polymer and (B) acrylic monomer. It is 2-20 mass parts, More preferably, it is 0.5-10 mass parts.

  (C2) As photopolymerization initiators, acyl phosphine oxide, oxime esters, aromatic ketones, quinones, benzoin ether compounds, benzyl derivatives, 2,4,5-triarylimidazole dimers, acridine derivatives, coumarins Compounds, N-phenylglycine derivatives, and the like. In addition, the photoinitiator used by this embodiment may be synthesize | combined by a conventional method, and a commercially available thing may be obtained.

  Among these, acylphosphine oxides, oxime esters, and aromatic ketones are preferred from the viewpoints of improving photocurability and increasing sensitivity and transparency of the cured film.

  In addition, a photoinitiator can be used individually by 1 type or in combination of 2 or more types.

<Acylphosphine oxide>
Examples of the acylphosphine oxide include bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide (commercial product: “IRGACURE-819” (BASF)), 2,4,6-trimethylbenzoyl-diphenyl-phos. And fin oxide (commercially available product: “LUCIRIN TPO” (BASF)).

<Oxime esters>
Examples of oxime esters include 1,2-octanedione-1- [4- (phenylthio) phenyl-2- (O-benzoyloxime) represented by the following formula (4) (commercial product: “IRGACURE-OXE01” (BASF 1)-[9-ethyl-6- (2-methylbenzoyl) -9H-carbazol-3-yl] ethanone-1- (O-acetyloxime) (commercially available product: “IRGACURE-OXE02” (BASF) )), 1-phenyl-1,2-propanedione-2- [o- (ethoxycarbonyl) oxime] (commercial product: “Quantacure-PDO” (Nippon Kayaku Co., Ltd.)) and the like.

<Aromatic ketone>
Aromatic ketones include benzophenone, N, N′-tetramethyl-4,4′-diaminobenzophenone (Michler ketone), N, N′-tetraethyl-4,4′-diaminobenzophenone, 4-methoxy-4′-dimethyl. Aminobenzophenone, 2,2-dimethoxy-1,2-diphenylethane-1-one (commercial product: “IRGACURE-651” (BASF)), 2-benzyl-2-dimethylamino-1- (4-morpholino Phenyl) -butan-1-one (commercial product: “IRGACURE-369” (BASF)), 2-methyl-1- [4- (methylthio) phenyl] -2-morpholino-propan-1-one (commercial product) : "IRGACURE-907" (BASF)), 2-hydroxy-1- {4- [4- (2-hydroxy-2-methyl- Propionyl) - benzyl] phenyl} -2-methyl - propan-1-one (commercially available: "IRGACURE-127" (BASF Corp.)), and the like.

<Quinones>
As quinones, 2-ethylanthraquinone, phenanthrenequinone, 2-tert-butylanthraquinone, octamethylanthraquinone, 1,2-benzanthraquinone, 2,3-benzanthraquinone, 2-phenylanthraquinone, 2,3-diphenylanthraquinone, Examples include 1-chloroanthraquinone, 2-methylanthraquinone, 1,4-naphthoquinone, 9,10-phenanthraquinone, 2-methyl-1,4-naphthoquinone, and 2,3-dimethylanthraquinone.

<Benzoin ether compound>
Examples of the benzoin ether compound include benzoin methyl ether, benzoin ethyl ether, and benzoin phenyl ether.

<Benzyl derivative>
Examples of the benzyl derivative include benzyl dimethyl ketal in addition to benzoin compounds such as benzoin, methylbenzoin, and ethylbenzoin.

<2,4,5-triarylimidazole dimer>
As 2,4,5-triarylimidazole dimer, 2- (o-chlorophenyl) -4,5-diphenylimidazole dimer, 2- (o-chlorophenyl) -4,5-di (methoxyphenyl) Imidazole dimer, 2- (o-fluorophenyl) -4,5-diphenylimidazole dimer, 2- (o-methoxyphenyl) -4,5-diphenylimidazole dimer, 2- (p-methoxyphenyl) ) -4,5-diphenylimidazole dimer and the like. Specific examples of 2- (o-chlorophenyl) -4,5-diphenylimidazole dimer include 2- (2-chlorophenyl) -1- [2- (2-chlorophenyl) -4,5-diphenyl-1, 3-diazol-2-yl] -4,5-diphenylimidazole and the like.

<Acridine derivative>
Examples of the acridine derivative include 9-phenylacridine, 1,7-bis (9,9′-acridinyl) heptane and the like.

<Coumarin-based compounds>
Examples of coumarin compounds include 7-amino-4-methylcoumarin, 7-dimethylamino-4-methylcoumarin, 7-diethylamino-4-methylcoumarin, 7-methylamino-4-methylcoumarin, and 7-ethylamino-4. -Methylcoumarin, 7-dimethylaminocyclopenta [c] coumarin, 7-aminocyclopenta [c] coumarin, 7-diethylaminocyclopenta [c] coumarin, 4,6-dimethyl-7-ethylaminocoumarin, 4,6 -Diethyl-7-ethylaminocoumarin, 4,6-dimethyl-7-diethylaminocoumarin, 4,6-dimethyl-7-dimethylaminocoumarin, 4,6-diethyl-7-ethylaminocoumarin, 4,6-diethyl- 7-dimethylaminocoumarin, 2,3,6,7,10,11-hexanehydro-1H, 5 -Cyclopenta [3,4] [1] benzopyrano- [6,7,8-ij] quinolizine 12 (9H) -one, 7-diethylamino-5 ', 7'-dimethoxy-3,3'-carbonylbiscoumarin, 3,3′-carbonylbis [7- (diethylamino) coumarin], 7-diethylamino-3-thienoxysilkine and the like can be mentioned.

<N-phenylglycine derivative>
N-phenylglycine derivatives include N-phenylglycine, N-phenylglycine butyl ester, Np-methylphenylglycine, Np-methylphenylglycine methyl ester, N- (2,4-dimethylphenyl) glycine, N-methoxyphenylglycine etc. are mentioned.

  (C2) The compounding quantity of a photoinitiator becomes like this. Preferably it is 0.1-20 mass parts with respect to 100 mass parts of total amounts of (A) acrylic polymer and (B) acrylic monomer, More preferably, it is 0.00. 1-10 mass parts, More preferably, it is 0.1-5 mass parts. By making the said compounding quantity into the said range, foaming, turbidity, coloring, and a crack of hardened | cured material can be prevented.

  The acrylic resin composition according to this embodiment may further contain (D) an antioxidant. Thereby, it becomes possible to prevent the oxidation of the polymerization terminal of (C) polymerization initiator and (A) acrylic polymer and (B) acrylic monomer remaining in the cured product after the curing reaction. As a result, the cured product is prevented from being colored, and an excellent visible light transmittance is obtained.

  (D) Antioxidant to mix | blend is although there is no restriction | limiting in particular, It is preferable to mix | blend the compound (henceforth a "hindered phenol type compound") which has a hindered phenol type structure.

（式（ＶＩ）中、Ｒ_７及びＲ_８はそれぞれ独立に、水素、直鎖状アルキル基又は分岐鎖状アルキル基を示す。なお、直鎖状アルキル基としては、メチル基、エチル基、プロピル基、ブチル基等が挙げられる。分岐鎖状アルキル基としては、イソプロピル基、イソブチル基、ｔ−ブチル基等が挙げられる。１分子中に式（ＶＩ）で表される基が複数あるとき、Ｒ_７及びＲ_８は、複数の基において、同一であっても異なっていてもよい。また、上記式（ＶＩ）中の芳香族環において、フェノール基、Ｒ_７及びＲ_８以外に、低級アルキル基等の基を有していてもよい。） In addition, as a hindered phenol type compound used by this embodiment, the compound which has at least 1 group (hindered phenol group) represented by the following general formula (VI) in 1 molecule is mentioned.

(In formula (VI), R ₇ and R ₈ each independently represent hydrogen, a linear alkyl group or a branched alkyl group. The linear alkyl group includes a methyl group, an ethyl group, and a propyl group. Group, butyl group, etc. Examples of the branched alkyl group include isopropyl group, isobutyl group, t-butyl group, etc. When there are a plurality of groups represented by the formula (VI) in one molecule, R ₇ and R ₈ may be the same or different in a plurality of groups, and in the aromatic ring in the above formula (VI), in addition to the phenol group, R ₇ and R ₈ , lower alkyl It may have a group such as a group.)

The hindered phenol compound used in the present embodiment is preferably a compound in which R ₇ and / or R _{8 in} the above formula (VI) is a branched alkyl group, and at least one of R ₇ and R ₈ is t- A compound having a butyl group is more preferable, and a compound in which R ₇ and R ₈ are both t-butyl groups is still more preferable.

  In addition, such a hindered phenol type compound may be synthesize | combined by a conventional method, and a commercially available thing may be obtained.

  As the hindered phenol compound used in the present embodiment, pentaerythritol tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propanoate] (commercially available product: “IRGANOX1010” (BASF)), Bis (3-tert-butyl-4-hydroxy-5-methylbenzenepropanoic acid) ethylenebis (oxyethylene) (commercial product: “IRGANOX245” (BASF)), 4-[[4,6-bis (octylthio) -1,3,5-triazin-2-yl] amino] -2,6-di-tert-butylphenol (commercial product: “IRGANOX565” (BASF)), 3- (3,5-di-tert-butyl -4-Hydroxyphenyl) octadecyl propanoate (commercially available product: “IRGANOX1076”) ASF)), N, N ′-(1,6-hexanediyl) bis [3,5-bis (1,1-dimethylethyl) -4-hydroxybenzenepropanamide] (commercial product: “IRGANOX1098” (BASF ), Tris (4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl) isocyanuric acid (commercial product: “CYANOX 1790” (American Cyanamide)), 6-tert-butyl-4- [3- [(2,4,8,10-tetra-tert-butyldibenzo [d, f] [1,3,2] dioxaphosphin-6-yl) oxy] propyl] -2-methylphenol (commercially available product : “Sumilyzer GP” (Sumitomo Chemical Co., Ltd.)), 3,9-bis [1,1-di-methyl-2- {β- (3-tert-butyl-4-hydroxy-5-methyl) Ruphenyl) propionyloxy} ethyl] -2,4,8,10-tetraoxaspiro [5,5] undecane (commercial product: “ADK STAB AO80” (ADEKA)), 2,2′-methylenebis- (4- Ethyl-6-t-butylphenol) (commercially available product: “Yoshinox 425” (API Corporation)) and the like.

  Among these, in particular, from the viewpoint of solubility, 3,9-bis [1,1-di-methyl-2- {β- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy} ethyl ] -2,4,8,10-tetraoxaspiro [5,5] undecane (commercially available product: “ADK STAB AO80” (ADEKA Corporation)) is preferred.

  In addition, these antioxidants can be used individually by 1 type or in combination of 2 or more types.

  The blending amount of (D) antioxidant is preferably 0.1 to 20 parts by mass, more preferably 0.1 to 100 parts by mass of the total amount of (A) acrylic polymer and (B) acrylic monomer. -15 mass parts, More preferably, it is 0.1-10 mass parts. By making the said compounding quantity into the said range, resin coloring at high temperature can be suppressed.

  The acrylic resin composition according to this embodiment may be further blended with a phosphor to make a potting material. The phosphor to be blended is not particularly limited, and examples thereof include Yttrium aluminum oxide (Sigma Aldrich).

[Electronic parts]
The electronic component according to the present embodiment will be described with reference to the drawings as the case may be. FIG. 1 is a cross-sectional view showing an embodiment of an LED package using the acrylic resin composition according to this embodiment.

  A liquid resin layer is formed so as to cover the peripheral region of the LED element 3 with a potting material obtained by dispersing the phosphor 2 in the acrylic resin composition according to the present embodiment described above, and then by thermosetting or photocuring. By curing the liquid resin layer, an LED package in which the resin layer (sealing member) 1 is formed so as to cover the peripheral region of the LED element 3 is obtained.

  The thickness t of the resin layer 1 is preferably 0.05 to 0.6 mm. When the thickness t is too small, the gold wire 5 and the LED element 3 are exposed, and it becomes difficult to efficiently emit the light emitted from the LED element 3 to the outside. On the other hand, when the thickness t is excessive, the amount of reflected light increases and the amount of light emitted to the outside decreases. On the other hand, if the thickness t is too large, the resin layer 1 has a low light transmittance, and the amount of light transmitted through the resin layer 1 is reduced, so that the light use efficiency is lowered.

  2 and 3 are process diagrams showing a manufacturing process of an LED package using the acrylic resin composition according to the present embodiment (FIG. 2 is a thermosetting type and FIG. 3 is a photocurable type).

  The resin layer 1 is formed by performing potting (resin pile) processing using a liquid acrylic resin composition. Specifically, after the liquid resin layer is formed so as to cover the LED element 3 by dropping the above-described potting material in a peripheral region surrounded by the light reflecting member 6 of the LED element 3, a heat treatment or an exposure process is performed. The resin layer 1 as a sealing member is formed by curing the liquid resin layer.

  The acrylic resin composition preferably has a viscosity that can prevent stringing when dropped, for example, the viscosity at 25 ° C. is 1 to 50000 mPa · s, more preferably 10 to 40000 mPa · s. More preferably, it is 100 to 10,000 mPa · s.

  As a material constituting the light reflecting member 6, a metal material such as aluminum or a resin material such as PPA (polyphthalamide) can be used.

  As the dimensions of the light reflecting member 6, for example, the opening diameter on the base end side in contact with the substrate is 1.5 to 4.5 mm, the opening diameter on the distal end side is 1.0 to 11.0 mm, and the axial length is 0. 0.1 to 5.0 mm, and the taper angle of the light reflecting surface is 60 °.

  In FIG. 2, the resin layer 1 contains the phosphor 2, and in FIG. 3, the resin layer 1 is shown as not containing the phosphor 2. However, in the effect obtained as the characteristics of the acrylic resin composition in the present invention, The presence or absence of the phosphor has no effect. Therefore, the phosphor 2 may not be included in the thermosetting type of FIG. 2 or may be included in the photocurable type of FIG.

  The acrylic resin composition according to the present invention has excellent visible light transmittance even in a thick film, and has excellent airtightness even under high temperature and high humidity. For this reason, the acrylic resin composition of the present invention is required to be miniaturized and mounted with high density, and is suitable as a sealing member for a light emitting element or a light receiving element such as an LED element used for a long time in a high temperature environment. That is, an electronic component including a light-emitting element or a light-receiving element and a sealing member that seals the light-emitting element or the light-receiving element, and the electronic component in which the sealing member is formed from the acrylic resin composition according to the present invention, The present invention can be applied as illumination for a camera used for a mobile phone or the like and a component of an LED display.

  EXAMPLES Hereinafter, although this invention is demonstrated more concretely based on an Example and a comparative example, this invention is not limited to a following example.

(A) component, (B) component, and (C) component are mixed by the mixture ratio (mass part, solid content ratio) shown in Table 1, and the resin composition of Examples 1-3 and Comparative Examples 1-4. Solution was obtained.
Each component in Table 1 is shown below.

((A) component)
Component (A) was synthesized by the following method.
300 g of tricyclo [5.2.1.0 ^2,6 ] dec-8-yl acrylate (commercial product: “FA-513A” (Hitachi Chemical Co., Ltd.)), 350 g of butyl acrylate (BA), butyl methacrylate ( 300 g of BMA), 50 g of glycidyl methacrylate (GMA) and 50 g of 2-ethylhexyl methacrylate (2EHMA) were mixed, and 50 g of lauroyl peroxide and 0.45 g of n-octyl mercaptan as a chain transfer agent were added to the resulting monomer mixture. Was dissolved to obtain a mixed solution.

  To a 5 L autoclave equipped with a stirrer and a condenser, 0.04 g of polyvinyl alcohol and 2000 g of ion-exchanged water are added as a suspending agent, and the above mixture is added with stirring. The mixture is stirred at 250 rpm and 5 ° C. in a nitrogen atmosphere at 60 ° C. Polymerization was performed for 2 hours at 90 ° C. for 2 hours to obtain resin particles (polymerization rate was 99% by mass method). The resin particles were washed with water, dehydrated and dried to obtain component (A). The weight average molecular weight of the obtained component (A) was Mw = 200000-250,000.

アクリル酸イソステアリル（エステル部に直鎖アルキル基を有する（メタ）アクリル酸エステル、市販品：「ＮＫ エステル Ｓ−１８００Ａ」（新中村化学株式会社））、及び

トリシクロデカンジメタノールジアクリレート（エステル部に脂環基を有する２官能（メタ）アクリル酸エステル、市販品：「Ａ−ＤＣＰ」（新中村化学株式会社））、を用いた。

((B) component)
Lauryl acrylate ((meth) acrylic acid ester having a linear alkyl group in the ester part, commercially available product: “LA” (Kyoeisha Chemical Co., Ltd.))

Isostearyl acrylate ((meth) acrylic acid ester having a linear alkyl group in the ester part, commercially available product: “NK Ester S-1800A” (Shin Nakamura Chemical Co., Ltd.)), and

Tricyclodecane dimethanol diacrylate (a bifunctional (meth) acrylic acid ester having an alicyclic group in the ester part, commercially available product: “A-DCP” (Shin Nakamura Chemical Co., Ltd.)) was used.

((C) component)
1,1,3,3-trimethylbutylperoxy-2-ethylhexanate (commercially available product: “Perocta O” (Nippon Yushi Co., Ltd.)), bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide (Commercially available product: “IRGACURE-819” (BASF)) and 2-hydroxy-1- {4- [4- (2-hydroxy-2-methylpropionyl) -benzyl] phenyl} -2-methyl-propane-1 -On (commercial product: "IRGACURE-127" (BASF)) was used.

  In Table 1, in Comparative Example 5, a silicone material for LED (commercial product: “OE6631” (Toray Dow Corning Co., Ltd.)) was used.

<Measurement of viscosity>
Using the cone composition viscometer (product name: “HB DV-III” (BROOKFIELD)), the resin compositions of Examples and Comparative Examples were subjected to predetermined times (rpm, 1) at 25 ° C. for 3 minutes. The viscosity when rotating at 60 sec- ¹ ) was measured. The measured value is obtained for a liquid kept at 25 ± 1 ° C. using a cone plate viscometer equipped with a cone having a cone angle of 1.5 ° and a cone radius of 12 mm.
The number of times per minute varies depending on the viscosity of the liquid to be measured. Specifically, the viscosity of the liquid to be measured is roughly estimated in advance, and every minute is determined according to the estimated value. In this specification, when the estimated value of the viscosity of the liquid to be measured is 6000 to 60000 mPa · s, the rate is 30 rpm, and when the estimated value of the viscosity is 1000 to 10,000 mPa · s, the rate is 50 rpm. When the estimated value of the viscosity is 200 to 2000 mPa · s, the number of times is set to 100 rpm. The results are shown in Table 1.

<Measurement of weight loss rate>
1 mL of the resin compositions of Examples and Comparative Examples were taken on a glass substrate, and the weight was measured. In the case of a thermosetting system, the weight measured was heated at 110 ° C. for 1 hour, then heated to 110 to 150 ° C. at 10 ° C./min, and further heated at 150 ° C. for 1 hour. On the other hand, in the case of a photo-curing system, it was completely cured at 8000 mJ / cm ² and heated at 150 ° C. for 1 hour. These were weighed again and the weight loss rate was calculated. The results are shown in Table 1.
Weight reduction rate (%) = 100 − {(weight of cured product after heating at 150 ° C. for 1 hour) / (liquid weight before curing) × 100}

<Measurement of initial transmittance>
The resin compositions of Examples and Comparative Examples were applied on a glass substrate using a spin coater (product name: “MS-A” (Mikasa Co., Ltd.)) so as to have a uniform film thickness. In the case of a thermosetting system, this was heated at 110 ° C. for 1 hour, then heated to 110 to 150 ° C. at 10 ° C./min, and further heated at 150 ° C. for 1 hour. On the other hand, in the case of a photo-curing system, it was completely cured at 8000 mJ / cm ² to obtain test substrates each having a resin layer with a thickness of 1 mm.

  The transmittance of this test substrate was measured using a UV-visible spectrophotometer (product name: “U-3310 Spectrophotometer” (Hitachi High-Technologies Corporation)) with reference to the transmittance of a single glass. Was measured. The results are shown in Table 1.

<Measurement of gas barrier properties>
The resin compositions of Examples 2 and 3 and Comparative Examples 1 to 4 were dropped on the LED package (FIG. 1), heated at 110 ° C. for 1 hour, and then heated to 110 to 150 ° C. at 10 ° C./min. Furthermore, it was cured by heating at 150 ° C. for 1 hour (FIG. 2). Similarly, the resin composition of Example 1 was dropped on the LED package (FIG. 1), and was exposed to 4000 mJ / cm ² under a nitrogen atmosphere and cured (FIG. 3). Similarly, the resin composition of Comparative Example 5 was dropped on the LED package (FIG. 1), heated at 100 ° C. for 2 hours, and then heated at 150 ° C. for 5 hours. Thereafter, the obtained LED package was heated at 100 ° C. for 2 hours in a 5 g / L sulfur atmosphere. This was soldered to a substrate, connected to a constant current power supply device by connecting wires, and the luminance was measured using an instantaneous multi-photometry system (product name: “MCPD-3000” (Otsuka Electronics Co., Ltd.)). In addition, the presence or absence of sulfuration in the silver lead frame (silver plating reflector) was visually confirmed. The results are shown in Table 1.
A: Luminance retention before and after exposure to sulfur gas is 90% or more.
B: The luminance retention before and after exposure to sulfur gas is less than 90%.

  From the results shown in Table 1, as (B) acrylic monomer, (meth) acrylic acid ester having an alicyclic group in the ester part and (meth) acrylic acid ester having a linear or branched alkyl group in the ester part It was confirmed that a low weight loss rate of 10% or less and high transparency were achieved by combining

  Therefore, the acrylic resin composition of the present invention has transparency and airtightness.

  The resin composition of the present invention has transparency and airtightness. Therefore, it is suitable as a sealing member for light-emitting elements such as LED elements that are used for a long period of time in a high-temperature environment with downsizing and high-density mounting.

  DESCRIPTION OF SYMBOLS 1 ... Resin layer, 2 ... Phosphor, 3 ... LED element, 4 ... Silver lead frame (silver plating reflective material), 5 ... Gold wire, 6 ... Light reflection member

Claims (7)

(A) an acrylic polymer, (B) an acrylic monomer and (C) a polymerization initiator,
The acrylic resin composition in which the (B) acrylic monomer contains a (meth) acrylic acid ester having a linear or branched alkyl group and a (meth) acrylic acid ester having an alicyclic group. The acrylic resin composition according to claim 1, wherein the (A) acrylic polymer contains at least one selected from the following general formulas (I), (II), and (III) as a structural unit.

(In formula (I), X represents an alicyclic group having 5 to 22 carbon atoms which may have a substituent, and R ₁ represents a hydrogen atom or a methyl group.)

(In formula (II), Y represents a linear or branched alkyl group having 1 to 10 carbon atoms which may have a substituent, and R ₂ represents a hydrogen atom or a methyl group.)

(In formula (III), Z represents a substituent containing at least one functional group selected from the group consisting of a carboxyl group, a hydroxyl group, an acid anhydride group, an amino group, an amide group, an epoxy group and a nitrile group; R ₃ represents a hydrogen atom or a methyl group.)   The acrylic resin composition according to claim 1 or 2, wherein the (A) acrylic polymer includes a structural unit derived from the same acrylic monomer as at least one of the (B) acrylic monomers.   Furthermore, the acrylic resin composition as described in any one of Claims 1-3 containing fluorescent substance.   The acrylic resin composition according to any one of claims 1 to 4, which is liquid at 25 ° C.   The acrylic resin composition according to any one of claims 1 to 5, which is used for a potting material. An electronic component comprising a light emitting element or a light receiving element and a sealing member for sealing the light emitting element or the light receiving element,
The electronic component whose said sealing member is the hardened | cured material of the acrylic resin composition as described in any one of Claims 1-6.

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